Hoist systems and cranes are used in a variety of applications for lifting a variety of materials. Construction sites often use hoists and cranes to lift building materials and the like. Another application relates to the lifting of signs and the installation of advertising copy at billboard sites. Advertising copy can include images placed primarily on vinyl films or wood. Wood is often used for extensions or cut-outs which extend above or beyond the typical rectangular-shaped billboard.
In the billboard industry, billboards are comprised of a billboard structure and faces. The faces are mounted on an area on the billboard structure where advertising copy is typically displayed. Advertising copy includes graphics, images, or text, and is usually placed on vinyl film or wood. The advertising copy can be changed when it is desirable to change the message or advertisement on the billboard. Alternatively, the billboard can utilize paper, cardboard, wood, plastic film, or other materials as the surface for holding the images which are attached to the face of the billboard.
Heretofore, the advertising copy was lifted onto the billboard faces manually, either by pulling a rope up by hand (roping), by utilizing generic block and tackle, or with the assistance of a crane truck. Roping can be strenuous and tiring, and requires younger, stronger people to perform this task on a regular and continuing basis. Utilizing generic block and tackle requires extensive set-up time and can require more than one person. Further, generic block and tackle is not well suited to the positioning requirements associated with advertising copy replacement on a billboard structure.
Crane trucks are relatively expensive pieces of equipment. Further, the use of a crane truck requires that the operating area surrounding the billboard be clear of obstacles, power lines, etc. Billboard structures are frequently located in remote areas or areas which are difficult to access. For example, billboard structures that are located in farmer fields, railroad right-of-ways, junkyards, parking lots, snowed-in areas, etc. are often difficult to access with a large piece of equipment.
United States Patent Application Publication U.S. 2001/0050263A1 discloses a portable aluminum jib crane with an attached nip roller drive system for lifting billboard vinyls. The nip roller drive system utilizes two rollers to raise and lower a flat rope. The drive roller assembly is mounted upon a subframe comprised of two square tubing members. The square tubing members can be mounted in a female square tubing member which is attached to a trolley. The trolley can be configured to ride on an I-beam associated with the billboard structure.
Heretofore, hoist systems for billboards have been complicated and heavy, requiring more than one person or the use of equipment to bring the hoist system to the top of the billboard structure. Further, such systems have been difficult to mount onto the billboard structure. Billboard structures vary in size and require a mounting system which can adapt to the various types of billboard structures.
Thus, there is a need for a hoist system which is portable and lightweight. Further, there is a need for a hoist system which can be easily attached on a variety of billboard structures. Further still, there is a need for a hoist system which is manufactured from relatively lightweight components. Yet further, there is a need for a low-cost hoist system. Even further still, there is a need for a hoist system optimized for the replacement of advertising copy.